﻿using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;

namespace WpfApp2
{
    class KeyHook
    {
        // #region 键盘钩子
        public delegate int HookProc(int nCode, int wParam, IntPtr lParam);
        static int hHook = 0;
        public const int WH_KEYBOARD_LL = 13;
        public const int WM_KEYDOWN = 0x100;

        public const int WM_KEYUP = 0x101;

        public int startindex = -1;

        //LowLevel键盘截获，如果是WH_KEYBOARD＝2，并不能对系统键盘截取，Acrobat Reader会在你截取之前获得键盘。  
        HookProc KeyBoardHookProcedure;

        //键盘Hook结构函数  
        [StructLayout(LayoutKind.Sequential)]
        public class KeyBoardHookStruct
        {
            public int vkCode;
            public int scanCode;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }

        //设置钩子  
        [DllImport("user32.dll")]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        //抽掉钩子  
        public static extern bool UnhookWindowsHookEx(int idHook);
        [DllImport("user32.dll")]
        //调用下一个钩子  
        public static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);

        [DllImport("kernel32.dll")]
        public static extern int GetCurrentThreadId();

        [DllImport("kernel32.dll")]
        public static extern IntPtr GetModuleHandle(string name);
        [DllImport("user32.dll", EntryPoint = "keybd_event")]
        public static extern void keybd_event(
           byte bVk,
           byte bScan,
           int dwFlags,  //这里是整数类型  0 为按下，2为释放
             int dwExtraInfo  //这里是整数类型 一般情况下设成为 0
       );
        public void Hook_Start()
        {
            // 安装键盘钩子  
            if (hHook == 0)
            {
                KeyBoardHookProcedure = new HookProc(KeyBoardHookProc);

                hHook = SetWindowsHookEx(WH_KEYBOARD_LL,
                KeyBoardHookProcedure,
                GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0);

                //如果设置钩子失败.  
                if (hHook == 0)
                {
                    Hook_Clear();
                    //throw new Exception("设置Hook失败!");  
                }
            }
        }
        //取消钩子事件  
        public void Hook_Clear()
        {
            bool retKeyboard = true;
            if (hHook != 0)
            {
                retKeyboard = UnhookWindowsHookEx(hHook);
                hHook = 0;
            }
            //如果去掉钩子失败.  
            if (!retKeyboard) throw new Exception("UnhookWindowsHookEx failed.");
        }
        public int KeyBoardHookProc(int nCode, int wParam, IntPtr lParam)
        {
            if (nCode >= 0)
            {

                Win32Api.KeyboardHookStruct KeyDataFromHook = (Win32Api.KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(Win32Api.KeyboardHookStruct));

                int keyData = KeyDataFromHook.vkCode;
                Key key = KeyInterop.KeyFromVirtualKey(keyData);
                if (wParam == 0x100)
                {
                    // 键盘按下0x100 
                    keybd_event(0x41, 0, 0, 0);//发送键盘消息a
                }
                return 1;//返回1表示拦截，返回0表示不拦截
            }
            else
            {
                return Win32Api.CallNextHookEx(hHook, nCode, wParam, lParam);
            }

        }


    }
}
